The much loved side kick to Mario & Luigi. After his first appearance in Super Mario World (no NES debut as he had to wait for super tech of the SNES). He then went on to star in many of his own games.
On a strange note, there is a very rare Yoshi game out there that is worth 2000-3000 dollars. Then there was also ability to eat the dolphins was removed from the US release but remained in the Japanese version.
At the end of the day hitting a question block & finding a Yoshi egg was always epic.